Apparatuses and methods of securing Global Navigation Satellite Systems are disclosure. In one exemplary embodiment, a mobile device may comprise: a communication interface configured to monitor signals from a plurality of satellites, a processor configured to determine impairment of one or more satellites in the plurality of satellites using the signals form the plurality of satellites, a memory configured to store a status of the determined impairment of one or more satellites in the plurality of satellites, and the communication interface that transmits the status of the determined impairment of the one or more satellites in the plurality of satellites to a server. The processor further determines a position of the mobile device using the status of the determined impairment of one or more satellites in the plurality of satellites, and stores the determined position and a corresponding digital certificate indicative of authenticity of the determined position in a memory.

A low-earth orbit (LEO) satellite includes a global positioning receiver configured to receive first signaling from a first plurality of non-LEO navigation satellites. An inter-satellite transceiver is configured to send and receive inter-satellite communications with other LEO navigation satellites. At least one processor is configured to execute operational instructions that cause the at least one processor to perform operations that include: determining an orbital position of the LEO satellite based on the first signaling; and generating a navigation message based on the orbital position. A navigation signal transmitter configured to broadcast the navigation message to at least one client device, the navigation message facilitating the at least one client device to determine an enhanced position of the at least one client device based on the navigation message and further based on second signaling received from a second plurality of non-LEO navigation satellites.

A positioning device includes: a first GNSS receiver a communication link configured to receive a spatial position, code measurements and carrier phase measurements of a second GNSS receiver; an input interface to a processing logic, the processing logic being configured to: calculate a position of the first positioning device from communicated data; and to estimate one or more parameters representative of multipath at the position of the first positioning device; wherein the communication link is configured to communicate to a second positioning device the parameters representative of multipath at the position of the first positioning device. Described developments comprise the use of multipath severity indicators, the determination of relative distances between receivers, validity conditions in time and/or space of multipath, various embodiments in a train or in a group of vehicles. Software aspects are discussed.

Apparatuses and methods of securing Global Navigation Satellite Systems are disclosure. In one exemplary embodiment, a mobile device may comprise: a communication interface configured to monitor signals from a plurality of satellites, a processor configured to determine impairment of one or more satellites in the plurality of satellites using the signals form the plurality of satellites, a memory configured to store a status of the determined impairment of one or more satellites in the plurality of satellites, and the communication interface that transmits the status of the determined impairment of the one or more satellites in the plurality of satellites to a server. The processor further determines a position of the mobile device using the status of the determined impairment of one or more satellites in the plurality of satellites, and stores the determined position and a corresponding digital certificate indicative of authenticity of the determined position in a memory.

A reinforcement information adjustment unit reduces an amount of information in reinforcement information by combining: update cycle adjustment processing to set an update cycle of the reinforcement information to be an integer multiple of a predetermined update cycle; geographic interval error value adjustment processing to reduce the number of geographic interval error values by selecting from among a plurality of the geographic interval error values each of which is an error at every predetermined geographic interval out of a plurality of error values, a geographic interval error value at every geographic interval that is an integer multiple of the predetermined geographic interval; and bit count adjustment processing to reduce a bit count of the error value for each error value. A reinforcement information output unit outputs, to an output destination, reinforcement information after being reduced in the amount of information by the reinforcement information adjustment unit.

A reinforcement information adjustment unit reduces an amount of information in reinforcement information by combining: update cycle adjustment processing to set an update cycle of the reinforcement information to be an integer multiple of a predetermined update cycle; geographic interval error value adjustment processing to reduce the number of geographic interval error values by selecting from among a plurality of the geographic interval error values each of which is an error at every predetermined geographic interval out of a plurality of error values, a geographic interval error value at every geographic interval that is an integer multiple of the predetermined geographic interval; and bit count adjustment processing to reduce a bit count of the error value for each error value. A reinforcement information output unit outputs, to an output destination, reinforcement information after being reduced in the amount of information by the reinforcement information adjustment unit.

A navigation satellite system, one or more NSS reference station is set out for providing information to one or more rover receivers. The NSS reference station comprises a processing unit configured to determine one or more first range intervals representing first ambiguity windows based on estimated atmospheric effects, and determine one or more second range intervals representing a second ambiguity window smaller than each of the first ambiguity windows based on uncertainties of range measurements within a predetermined previous period. The NSS reference station further comprises a transmission unit configured to transmit, to the NSS rover receivers, first messages each comprising a modulo a first ambiguity window, and transmission of two first messages, to range measurement transmit between the NSS rover receiver, a plurality of second messages, each second message comprising a range measurement modulo one of the second ambiguity windows.

Systems and methods for sharing convergence data between GNSS receivers are disclosed. Convergence data received at a GNSS receiver via a communication connection may be utilized to determine a position of the GNSS receiver.

A Global Positioning System (GPS) receiver, a control method of the GPS receiver, and a GPS system are provided, which are capable of reducing an initial position check time using an SBAS signal transmitted from a SBAS satellite. The control method of a GPS receiver includes receiving an SBAS signal from a SBAS satellite and calculating a satellite clock and a satellite position of the GPS receiver using the received SBAS signal. The SBAS signal may contain a difference value between the ephemeris data and the almanac data of the GPS satellite. The difference value between the ephemeris data and the almanac data may include a satellite clock difference value and a satellite position difference value for the GPS satellite. Accordingly, it is possible to acquire the current position and time information more quickly and accurately, by shortening the initial position check time using the difference value between the ephemeris data and the almanac data included in the SBAS signal.

An augmentation information adjustment unit (102) reduces an amount of information in augmentation information by combining: update cycle adjustment processing (1021) to set an update cycle of the augmentation information to be an integer multiple of a predetermined update cycle; geographic interval error value adjustment processing (1022) to reduce the number of geographic interval error values by selecting from among a plurality of the geographic interval error values each of which is an error at every predetermined geographic interval out of a plurality of error values, a geographic interval error value at every geographic interval that is an integer multiple of the predetermined geographic interval; and bit count adjustment processing (1023) to reduce a bit count of the error value for each error value. An augmentation information output unit (103) outputs, to an output destination, augmentation information after being reduced in the amount of information by the augmentation information adjustment unit (102).